Low Hemoglobin, Higher Risk? New Study Links Anemia to Dementia in Older Adults

An Overlooked Risk Marker in Brain Health

Anemia is often seen as a common issue in older adults, especially in people living with chronic conditions such as kidney disease, autoimmune disorders, or inflammatory bowel disease. But emerging evidence suggests it may have broader implications than previously thought. A recent study published in JAMA Network Open found that older adults with anemia were more likely to have higher levels of Alzheimer’s-related blood biomarkers and faced a greater long-term risk of developing dementia.

The findings add to growing interest in how systemic health conditions may interact with neurodegenerative disease. In this study, the highest dementia risk was observed in participants who had both anemia and elevated levels of Alzheimer’s-associated biomarkers, suggesting that low hemoglobin may be part of a larger biologic context linked to cognitive decline.

What the Study Looked At

Researchers analyzed data from 2,282 adults aged 60 years or older who were part of the Swedish National Study on Aging and Care in Kungsholmen. None of the participants had dementia at baseline. The investigators assessed anemia using World Health Organization criteria based on hemoglobin levels and also measured several blood biomarkers associated with Alzheimer’s disease. They then followed participants over time to evaluate who went on to develop dementia.

At baseline, 8.7% of participants had anemia. Compared with those with normal hemoglobin, this group was generally older, more likely to be male, had a lower education level, and carried a greater burden of chronic disease. Importantly, participants with anemia also had higher levels of Alzheimer’s-related biomarkers in the blood.

A 66% Higher Dementia Risk

Over a follow-up period of up to 16 years, with an average follow-up of 9.3 years, 15.9% of participants developed dementia. The key finding was that anemia was associated with a significantly greater likelihood of future dementia. Participants with anemia had a 66% higher risk of developing dementia than those with normal hemoglobin levels.

This association remained even after excluding individuals who had mild cognitive impairment at baseline or who were diagnosed with dementia within the first six years of follow-up. That strengthens the argument that anemia may be more than just a bystander condition in older adults already on the path to cognitive decline. However, the association was not seen among carriers of APOE-ε4, a genetic variant known to increase Alzheimer’s risk.

When Biomarkers and Anemia Combine

The study also highlighted a potentially important interaction between hemoglobin levels and Alzheimer’s-related biomarkers. Dementia risk increased as hemoglobin levels fell and biomarker levels rose. In contrast, participants with normal hemoglobin and low biomarker levels had the lowest risk.

One biomarker drew particular attention: neurofilament light chain, or NfL, which is considered a marker of neuronal injury. When anemia and elevated NfL occurred together, dementia risk appeared especially pronounced, suggesting an additive effect. The authors also reported that some associations seemed stronger in men than in women, although they urged caution in interpreting these sex-specific findings. 

Why the Findings Matter 

From a clinical perspective, the results raise an important question: should anemia receive more attention during cognitive assessment in older adults? Because anemia is easy to detect through routine blood testing and is often treatable, it may represent a potentially modifiable factor in dementia prevention strategies.

Still, the study authors and outside experts were careful not to overstate the findings. This was an observational study, meaning it shows association rather than causation. It does not prove that anemia causes Alzheimer’s disease or dementia, nor does it show that treating anemia will prevent cognitive decline. Rather, it suggests that low hemoglobin may be a clinically meaningful signal that helps identify people who warrant closer monitoring or a more complete cognitive evaluation. 

Important Limitations to Keep in Mind

• Observational design cannot establish causality
• Some dementia diagnoses and self-reported data may be inaccurate.
• Most anemia cases were mild or typical, limiting subgroup analysis.
• Biomarkers were measured only at baseline.
• The cohort was region-specific and mostly white, limiting generalizability.
• Exclusion of older, sicker participants with missing data may have underestimated the association. 

Conclusion

Anemia alone is not a diagnostic sign of dementia. But this study suggests it should not be dismissed as an incidental finding in older adults, especially those with memory concerns. Low hemoglobin may be one more piece of the puzzle in understanding who is at greater risk of cognitive decline. For now, the message is not that anemia explains dementia — but that it may deserve a closer look in the broader conversation about brain health and aging

Source

1.    doi:10.1001/jamanetworkopen.2026.4029

2.    MedicalNewsToday – access April 2026